#include <bits/stdc++.h>       // std::cout
using namespace std;
int main ()
{
   priority_queue<int> foo,bar;
   foo.push (15); foo.push(30); foo.push(10);
   bar.push (101); bar.push(202);
 
   foo.swap(bar);
 
   cout << "size of foo: " << foo.size() << '\n';
   cout << "size of bar: " << bar.size() << '\n';
 
   return 0;
}
